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In the March/April 2017 magazine of Elektor there is an article about lead-acid battery activator. This can also be used to measure the quality of the batteries. This has been done by measuring the internal resistance. The lower the better.

Interested? And do you have questions? Please place your question in this Forum

My kit arrived late last week and I finally managed to get to put it together. It took about an hour to have it up and running. The build went very smoothly.

I first tried it on an older 12V 7Ah battery and had some decent results, but it wasn't really telling me anything, so I connected both the activator and battery to my power supply and charged the battery while activating it. I left it over night, and was amazed how a battery that was reading 8V and wasn't providing any power was now almost like new! Next I tried a car battery that I had to replace this winter. It would test OK when I took the battery in for warranty replacement, but it still wouldn't start the car in the morning! The tester that shops use to test their batteries do not do a very good job, as the clerk said he would do a load test on the battery and call me in an hour. I had a call back saying that the battery was shot, and that it did need replacement.

I put the activator on it with the power supply and let it run overnight. This morning, the Vt was 13.1, I was 105, and the amazing thing was that R was 6.22, whereas it was around 11 when I started the process.

I have 10 used batteries in my solar power array, and they were all faulty to some extent, so I got them for free. Tomorrow I am going to go through each one and do my best to re-activate them all.

This has to be the best, most useful, gadget that I have made in a very long time.

After using this for a few days, I find that the readings I get are inconsistent. My suspicion is that the timings that you are using are just too tight. You are trying to meet an arbitrary 100 microsecond pulse, but this really doesn't matter. If to extended the pulse time to 125uS or 150 uS, you would have more time for the A/D's to settle, and likely get more consistent readings.

Just because someone else used 100uS doesn't mean you need to. 500uS might even help the process, although if left on all the time, it would drain the battery 5 times as fast. Have you tried extending the time?

Sorry for the very late reaction. As far as I understand the activator improved the internal resistance of your battaries. I didn't know that the goood result is there already after one night.

Your are right, the pulse duration can be longer than 100 usec. Wityh about 100 A and a repetition rate each 30 seconds the average current will be 100 * 10^-4/30 ≈ 0.3 mA. Thus a longer pulse time will increase this avarge current, but it is still (very) small compared to the current taken by the rest of the electronics (especcially the 5-15V DC-DC convertor unfortunately takes a lot of power). Care must be taken with larger pulse times for the fuse, diode, shunt and MOSFET.

The flowcode as part of the article (March/april 2017) has been written in Flowcode 6. Please find here the Flowcode 7 versions, with some changes in the C-parts (Capitals for registers and test_bit instead of ts_bit).